Plants 0.1-10(-12) dm across. Leaves: petiole 0.2-0.6(-1) cm; blade 0.3-2 × 0.5-2.5(-3) cm. Involucral bracts 1-1.5(-3) × (1.5-)2-3(-3.5) mm. Flowers: perianth 0.9-1.2 mm; filaments 0.5-0.6 mm; anthers 0.2-0.3 mm. Achenes 1.2-1.5 mm. 2n = 28.

Flowering Mar-Jul. Sandy to gravelly soils in shady places in grassland and chaparral communities, and in oak-pine or occasionally montane conifer woodland; 0-1600 m; Ariz., Calif., Nev., Utah; Mexico (Baja California).

The only presumed Oregon collection of Pterostegia drymarioides (Tolmie s.n., GH) was gathered along the Columbia River sometime in the 1830s. The only collection reportedly from New Mexico (Parry et al. 1171, US) supposedly was found in the Rio Grande Valley in the 1850s during the United States-Mexico Boundary Survey. The species likely will be found in southern Oregon (not northern), but it is unlikely that it ever occurred in New Mexico. A problem is that this species is often difficult to notice, as the plants tend to be in the shade under shrubs. Specimens often are misidentified as Parietaria (Urticaceae)—See Flora of North America volume 3, pages 406-408.